Over the past year, the Royal Canadian Mounted Police in the Kamloops and Merritt areas have noted an increase in the number of crashes involving ball and hitch trailers. In some of the cases investigated, fatal injuries have resulted.
This problem is of great concern to the R.C.M.P. in our efforts to reduce crash fatalities and injuries. Not all of the incidents when they occur are reported to the police due to the fact there was no crash and the driver was able to regain control of the unit.
Information obtained from both the R.V. manufacturers and suppliers suggest this problem is much larger than we expected. Additional information provided from RV clubs also suggests the problem is quite large. Examination of the crashes investigated resulted in a number of consistencies being surfaced. In the majority of the crashes, the towing vehicles were fitted with electronic brake controllers.
These controllers are accompanied by a sheet of instructions on both the installation and set up of the systems. Some of these controllers also include a ?Gain? control, which the operator can adjust either up or down depending on the driving situation, such as loading and road conditions. In the cases where crashes have occurred, the gain control was noted to be turned to its lowest setting. In these cases, the brakes on the towed unit may not activate.
Where the vehicle was in a turning situation with brakes being applied by the towing vehicle, the trailer would tend to push the rear of the towing vehicle causing rotation and possible control loss.
The mounting and leveling of the brake controller is also of some concern. The improper mounting of the electronic unit can make it ineffective. The printed instructions state the following, ?The level adjustment is CRITICAL.? They go on to indicate level adjustment determines whether automatic braking response is delayed or aggressive. This delayed or lack of response will result in the trailer pushing the towing vehicle while aggressive braking could result in trailer wheel lockup, which could result in control loss of the trailer.
It is probably the aggressive brake response that is prompting driver to reduce the gain on their controllers thereby reducing the braking effectiveness of their trailers.
Another fact uncovered in the crash investigations was the inflation pressures of the tires on the towing vehicles. In all cases, the tires were under inflated. This causes the sidewalls to be flexible and the towing unit to sway, which can, when the towing vehicle brakes, add to the instability caused by the trailer pushing.
Drivers should consult their vehicle manufacturer/tire supplier when attempting to tow a large trailer to determine proper inflation levels. Information obtained from one manufacturer recommends drivers, when towing large trailers, run their tires at maximum inflation pressures. This information can be found in the vehicle owner?s manual and on the door-post of the vehicle. The owner?s manual will have detailed information regarding towing procedures.
In the case of tires, staying with the same or a higher rated tire on the towing vehicle is recommended for the stability of the vehicle. Lowering the tire rating may result in a stability problem due to the weaker side walls. This also applies to the trailer tires as well. The lowering of the tire rating also reduces the amount of weight the tire is able to safely carry.
Hitch loads are also a factor in why control loss may be occurring. Trailers typically have their designed centre of mass located between the axles or in the case of a single axle trailer, slightly ahead the axle. When loaded for a trip, owners may be loading items in such a manner as to lessen the recommended hitch loads. For example, a family leaves home with the trailer loaded including water. The hitch load at this time may be near or below the recommended. Once at their destination, the family uses the stored water and other perishable items, fills the waste tanks some of which are located at the rear and some at the axle. When leaving the area they may fill the water tank and be unable at that time to dump the waste. This can create a negative hitch load. This will create a dangerous steering and control problem. If we add to this the improper setting of the brake controller, we have a potential for disaster.
Hitch load rating can be found in the vehicle owner?s manual. For example, on the 2000 Chevrolet Tahoe, it is recommended hitch loads be 10 to 15%.
One manufacturer indicates in their manual to ensure proper weight distribution by keeping the load balanced. Keep the center of gravity low for the best handling. The load should be approximately 60% to the front of the axle and 40% to the rear, keeping within the limits of the manufacturer?s tongue weights.
Make sure the load is balanced side to side and is secured to prevent shifting which can affect handling during cornering and braking.
Manufactured trailers typically do not come fitted with shock absorbers. The addition of shocks to the trailer suspension can greatly increase the handling characteristics, without these there is no damping when the trailer encounters rough or uneven road surfaces.
Maintenance of the trailer suspension is an additional area where tight and well-maintained wheel bearings etc. will aid in trailer stability. Poorly maintained suspensions, due to movement and shifting within the parts could contribute to instability.
Breakaway devices should also be serviced on a regular basis. Police roadside inspections of trailers regularly find cables hooked up improperly, batteries without charge or no battery at all. A check of the switch and testing of the unit will surface these deficiencies.
It is recommended that all those persons towing ball and hitch trailers consider having their brakes and brake controllers installed and set by a professional and the directions provided by the manufacturer be followed to the letter.
In situations where the braking of the trailer is aggressive such as city driving and the gain is reduced to compensate ensure once back on the open road, the system is reset.
Learn and perform trailer ?tug-tests?.
Changes in trailer loading and/or changes in road conditions require a re-adjustment of the brake controllers gain.
If you encounter a situation where your unit is handling in an unusual manner, have it checked by a professional before a tragedy occurs.
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